


Sister Complex

by Drowned_Ophelia



Category: Persona 4
Genre: Extremely Underage, F/M
Language: English
Status: Completed
Published: 2016-07-12
Updated: 2016-07-12
Packaged: 2018-07-23 12:33:08
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 4,279
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7463481
Author URL: https://archiveofourown.org/users/Drowned_Ophelia/pseuds/Drowned_Ophelia
Summary: <blockquote class="userstuff">
              <p>Nanako is jealous of how much Adachi is hogging her Big Sis while she's in town. She tries to figure out just what's so special about Adachi...</p><p>Written for a former friend, but I guess I'll still keep this up.</p>
            </blockquote>





	Sister Complex

**Author's Note:**

> ...You ever get an idea in your head and run with it? It started out with wondering just how Nanako would feel once Adachi and a female protagonist started dating. If you're sensitive to sexual content with kids, please don't read any further. I tried to make it as "tasteful" as I could, but it still might be pretty upsetting to a lot of people. 
> 
> I've been sitting on this for awhile, thinking about posting it, so it's been awhile since I read it over. Pardon me if there's any serious errors.

Nanako stared at them with jealousy in her eyes. Her Big Sis had finally come from the city for a visit and to celebrate her eighteenth birthday with the family that mattered most to her. Nanako had thought this would mean being able to make up a little of the time they’d lost together during her long hospital, but it seemed she had competition.

Things had started out normally enough. Narukami had arrived late one evening and greeted Nanako with a big hug and a few gifts, but the next day was when it got weird. Adachi had joined them for the belated party, Narukami shocking both her cousin and uncle when she suddenly announced she and Adachi had decided to start dating.

Dojima had seemed to have taken it fairly well, but Nanako missed the long conversation he’d had with them after she went to bed. All Nanako cared about was since then Adachi just wouldn’t go away.

Narukami would be there for awhile, but Nanako’s hopes got smaller and smaller of being able to spend one-on-one time together. She hadn’t been forgotten in the slightest, but didn’t like Adachi tagging along as well.

It didn’t matter he had just now treated the three of them to ice cream. Nanako had barely touched hers, holding a cup of the strawberry flavored treat and swirling the spoon around inside it while she sat and watched Adachi and Narukami, who were sitting across from her at the small circular table.

Adachi reminded Nanako of a tick how he seemed to always be touching Narukami in one way or another, even if it was just having his arm against hers. His chair couldn’t be any closer and he took the liberty to take a small lick off of Narukami’s cone without asking.

“I should have gotten that flavor,” Adachi commented.

“Would you like to trade?” Narukami asked sweetly. “I don’t mind.”

“That’s alright.” Adachi turned to Nanako. “What’s wrong? If it’s doesn’t taste good I can-”

“It’s fine.” Nanako took a bite, barely tasting it. “Don’t you have to work?”

“I actually took some time off.” Adachi couldn’t help smiling at Narukami. “Things have been pretty quiet now so they can get along without me.”

“But what will they do without someone to get the coffee?” Narukami asked jokingly, the first time she’d ever seen Adachi at the police station sticking out in her mind.

“You brat!”

Nanako slumped even further into her chair as the couple laughed. She’d completely lost her appetite so Adachi finished off her ice cream while she secretly hoped he’d get fat.

Finally they were going to go home, Nanako rushing to Narukami’s side to hold her hand. What she didn’t anticipate was Adachi then offering her his as well, but she accepted just to finally put some space between him and her Big Sis.

“I’ll be just a minute,” Narukami said when they’d reached the house and Nanako tried to pull her inside.

“I won’t keep her too long,” Adachi assured.

“…OK,” Nanako replied dully before entering the house.

Her father didn’t seem to be downstairs, so Nanako hoisted herself up onto the kitchen counter to pull back the curtain and look out the window at the two lovers. Under the cover of the relentless fog and fading daylight Adachi had pulled Narukami in close, his tongue in her mouth with his hand under her skirt, while he grabbed her ass.

“Nanako, what are you doing?”

“Huh?” Nanako nearly fell off the counter as she turned back to see her dad. “Big Sis and Adachi-san are-”

“Hey, don’t spy on them,” Dojima scolded gently before helping Nanako down.

“But-” Nanako tried to tell her father what she’d just witnessed, but Narukami finally came inside with Adachi following, showing no signs of how aggressive he’d been.

“Just thought I’d drop in and say ‘Hi’.” Adachi knew Dojima still had reservations about him dating his niece, so he was being on his best behavior and doing everything to impress him. He’d still see Narukami no matter what his boss thought, but not having to seek around anymore was so much more convenient.

“Tohru treated us to ice cream today.” Narukami contributed to make Adachi look even better in Dojima’s eyes. “Wasn’t that nice of him, Nanako-chan?”

“…I guess,” Nanako grumbled.

“Are you feeling alright?”

“Yeah, I’m fine.”

“You’ve been so excited for her to visit you didn’t sleep much,” Dojima recalled, hoping it was just fatigue that was making Nanako look so glum. He looked to Narukami. “I’m going to be working some overnight shifts the next few days. Sorry to put you in this position again, but they need the help. Can you look after her?”

Narukami nodded. “Of course.”

The corner of Adachi’s mouth curled slightly upon hearing this.

 

Nanako made sure to make the most of what time was left before bed. She asked Narukami to draw with her, paint her nails, and then requested a bedtime story.

“Do you really like Adachi-san?” Nanako asked out of the blue.

“Very much.” Narukami smiled warmly at just the thought of him.

“I think Yosuke will be sad.”

“Oh… Well…” The smile was quick to fade. “None of them know I’m here, so they won’t find out for awhile. To tell you the truth… We haven’t kept in contact very well…”

What had happened in December had taken a harsh toll on all of them. It had gotten to the point where even being with each other was too painful of a reminder that there was more to the case they couldn’t figure out.

On Narukami’s end, it was losing Teddie and needing to play dumb around them that was the hardest. She felt no guilt for letting Adachi get away with Yamano and Saki’s murders, but protecting him and trying to encourage the Investigation Team to drop it without seeming suspicious had been tiring. Really, it would be for the best if she kept avoiding them.

“They came and visited me in the hospital. Yosuke said-”

“I’m so sorry, but I really don’t want to talk about that right now. I’m glad to spend time with you, Dojima-san, and Tohru.”

“Can we have a day just for us?”

“Of course. Oh…” Suddenly Nanako’s behavior made sense. “Did you feel left out today?”

Nanako nodded.

“Well, I promise that we’ll have some days to ourselves.”

“Thank you!” At last Nanako flashed that cheerful smile that Narukami adored so much before giving her a hug.

Adachi understood the feeling quite well of wanting to keep Narukami all to himself when told. He allowed the two girls to have their “sister time” during the next day; it was the night he was interested in.

Nanako stirred upon hearing the floor creak outside of her room. She sat up in bed, rubbing the sleep out of her eyes as she listened carefully to the creaks getting softer and further away.

She got out of bed and crept carefully to her door, opening it slowly just in time to see Narukami tiptoeing quietly towards the stairs. Nanako waited a moment before following, her smaller frame allowing her to move silently. Upon reaching the staircase herself she could voices, but was unable to make out what they were saying.

Very slowly she began her descent, not wanting to alert anyone. Unsurprisingly, it was Adachi who’d sent Narukami a text and gotten her out of bed at such an odd hour. Nanako pouted at once as she peeked at them but stayed put.

“Shouldn’t I get dressed so we can go to your place?” Narukami asked quietly as she and Adachi sat on the couch.

“No. I was thinking about the time I fucked you here right in front Dojima…” Adachi chuckled as he reached forward to play with her hair, twirling a strand around his finger. “He was so wasted that even when he did open his eyes he didn’t realize what we were doing…”

Narukami remembered it well; her heart was pounding the entire time. Adachi had been especially cruel that evening, bending her over the table so she had to face Dojima while he thrust into her from behind. Being so nervous she hadn’t even been able to cum, but let Adachi finish.

“Let me at least turn the light off. If Nanako gets up and sees it on…”

“We’ll be fine. You look great in that nightgown… I can’t wait until you’re sleeping next to me wearing outfits like that every night…”

She knew she shouldn’t be watching. She knew that this was adult stuff. She knew it was something she’d never be able to forget. Still, Nanako stayed put as the two kissed, a seductive look on Narukami’s face. The small girl would have been easy to spot if they looked her way, but they were much too focused on one another.

Adachi slid down one of the straps of Narukami’s periwinkle nightgown, kissing and sucking on her shoulder as he did the same with the other. He loved having her in such little clothing, her breasts exposed without having to fuss with a bra hook.  
Nanako’s eyes went wide to see Adachi fondling Narukami’s chest, commenting how the pictures she’d sent him couldn’t help how much he’d missed being able to touch them. She had the best pair of tits he’d ever seen in his life, pressing her breasts together so he could suck on both of them.

A pleasure filled moan escaped Narukami’s lips. “I love you more than anything, Tohru…” she said as she ran her fingers through his hair. “You’re all I could think about.”

Adachi stopped to respond. “Even more than cats?” he joked.

She giggled. “Of course!”

“I love you, too.” Those words still felt strange for him to say, but it got easier and easier each time, and he genuinely meant it.

Meanwhile Nanako felt like daggers were piercing her heart as tears ran down her cheeks. Her Big Sis, who she practically worshipped, loved Adachi more than her. Nanako had grown fond of Adachi because of how much time he’d spent in her home, but she couldn’t understand how a clumsy guy who frequently had holes in his socks could have so much appeal to Narukami.

The more she thought about it, the worse her tears got, blurring her vision. While Nanako wiped them away Adachi was wasting no time in lifting up Narukami’s nightgown to find she didn’t have any panties on either. A quick stroke revealed she had quickly become wet for him, like always.

The next thing Nanako saw was Narukami on her knees in front of Adachi, having just unzipped his pants and taken his dick out. Nanako knew what the difference was between boys and girls but was baffled when she saw Narukami kiss the shaft fondly before flicking her tongue over the tip.

Adachi groaned when she took all of him inside her mouth. This was one of the sensations he’d longed for again, but their time apart had made the pleasure that much more intense. Narukami’s skills hadn’t dulled at all and he soon made her stop; he wanted finish inside her pussy.

“Lay down,” Adachi directed hastily, nearly shoving her back onto the make her hurry up.

He’d stayed true to her during these agonizingly long months, using his hand to get off instead of finding some floozy in bar to fuck until he could be with her again. Her body was just as he remembered it, now easily able to take all of him inside, but still so tight.

To Nanako it looked like he was hurting her. She knew the difference between boys and girls, but didn’t understand how Adachi could be doing such a thing. Narukami was crying out with nearly every thrust, a few tears of her own falling down her face.

“Be careful or you’ll wake Nanako-chan…” Adachi reminded with a sneer.

Narukami gasped and cupped her hand over her mouth.

That’s right! They didn’t want her awake! If only she’d acted sooner! Nanako got up off the step and hurried back upstairs. “Big Sis? Where are you?” she called.

“Shit!” Adachi hissed, pulling out of her at once and tucking his dick back inside of his pants, Narukami covering herself back up as well.

“I’ll be right there, Nanako!” Narukami called back. “Just stay right there!” She looked back at Adachi. “I’m sorry…”

He sighed and shrugged. “My place next time.”

“I promise I’ll make it up to you.”

After a quick peck on the lips Adachi was out the door, Narukami quickly looking to see if they’d made a noticeable mess before hurrying upstairs.

“Are you OK?” Narukami asked.

Nanako nodded. “I just heard noises.”

“I didn’t mean to wake you.”

“That’s OK. Can I sleep next to you?”

“Sure.”

This proved to be a mistake. While Narukami was soft and nice to snuggle up to as always, Nanako could smell Adachi’s cheap cologne. This wasn’t fair. Even when he was gone his presence still lingered on Narukami.

 

Nanako had never been so frustrated to be little. Her young, innocent mind just couldn’t put the pieces together as to what was so appealing about Adachi. She asked questions, some of which no one would give her a straight answer to, Adachi only making an awkward sound and excusing himself at one point when she asked if he only liked Narukami due to her chest size.

Two nights later Adachi had decided to mooch dinner off of them. He helped himself to some beers in the fridge, ending up so buzzed Narukami insisted he spend the night on the couch. It wouldn’t be the first time, Adachi quite comfy as he laid on his back and Narukami tucked him in.

“Gimme a kish…” Adachi slurred.

Narukami was used to him tasting like beer, not flinching at all when their mouths made contact. They bid each other a “good night” before Narukami headed upstairs. Adachi was out like a light, soon snoring after entering a deep sleep.

Nanako saw this as her chance. She waited a few hours before sneaking out of bed and venturing downstairs to Adachi. He was still out cold not even moving when Nanako got on top of him and straddled his torso.

Up close Nanako was still puzzled. In his sleep Adachi looked even sloppier, slack jawed and hair a complete mess. Still, there’s no way Narukami would fall for someone without a good reason. Nanako thought about the things she’d seen Adachi do to her. She placed her hands on her flat as a cutting board chest. There was nothing there yet for Adachi to grab so she could experience that.

She leaned forward in an attempt to kiss him, but she couldn’t endure his horrible breath the way Narukami could and backed out. That just left one more area of exploration…

Nanako got off Adachi and carefully pulled back the blanket from his feet until his crotch was exposed. She unzipped his pants, looking up to see if Adachi was waking up at all before sticking her hand down his boxers and pulling out his flaccid dick.

She was confused as she stared at it. Why had it been curved upwards when Narukami had done it? She leaned over and touched it, feeling the veins over the smoothness. Why had she licked it, for that matter…?

The only way to find out was to try. Nanako leaned over and dragged her tongue along his length just like how she’d seen. This seemed pointless. Did she have to put it in her mouth? It seemed way too big for that… She licked the tip as well, crinkling her nose at the funny taste. She opened her mouth as wide as she could like she was at the dentist and tried to take him into her mouth.

Adachi let out a small grunt in his sleep. He soon awaked as he realized that Narukami must have come down to give him a surprise blowjob, but why did he hear gagging? “Are you so desperate that…” He froze as he sat up and saw the girl he never expected with the head of his dick in her tiny mouth. “What the hell?!”

As Nanako stepped away Adachi felt his head spin. This couldn’t be real. This was a dream. No way would a first grader have just been attempting to suck him off. He kept trying and trying to wake up, sobering at once when he realized the truth and tucked himself back in.  
“Why would you do that?!” Adachi barked, sickened.

“I-I saw you and Big Sis…” Nanako cowered under his gaze; she’d never seen Adachi angry before.

She’d seen them that night?! Adachi just wanted relive one of the most exciting times he’d had fucking his girlfriend, not scar the only little kid he cared about for life . It wasn’t often he was able to feel guilt, but now it hit him like a ton of bricks; there was no way he couldn’t see this as his fault.

“Dammit…” How on earth did he handle this? “Your sister and I are adults in a relationship! Don’t you EVER do any of those things until you’re her age! Didn’t your dad teach you not to touch or let anyone touch you down there?!”

Nanako was trembling. If she weren’t so scared she’d be crying her eyes out. “I just wanted to know why…”

“Why what?” he snapped.

“…Why she loves you so much…”

The anger melted away from Adachi’s face. After what Narukami had told him, and what he’d seen for himself, he should have known. “To be honest, I wonder that sometimes too. Love doesn’t always make sense, but I know what I have with her I’ll never have with another person. Can you understand that at all?”

Nanako wasn’t sure, but was afraid what saying what sort of response a “No” would get her.

Adachi ran his hand down his face. “It’s late… If we need to, we’ll talk about it later.”

“Are you gonna tell Big Sis?” Nanako asked meekly.

“No. Go back to bed now, alright?”

Nanako nodded before dashing back to her room.

Adachi tried to lay back down, but realized he couldn’t stay there. What Nanako had done kept flashing in his mind, making his skin crawl. If Nanako had been in her teens it would be a different story, but… He shook his head. He’d squeeze in next to Narukami and get up before Dojima got back.

 

“OH NO! NOT IN MY HOUSE!”

Nanako awoke with a start when she heard thumping, opening her door to see her father dragging Adachi out of Narukami’s room by his shirt collar. They’d both slept much later than they’d anticipated, Dojima having burst in when he saw Adachi’s shoes by the door and his absence on the couch.

Adachi was trying to get to his feet, nearly being strangled by his boss who looked about to burst a blood vessel.

“We didn’t do anything! I swear!” Narukami insisted as she followed.

Dojima wasn’t listening. “I don’t have a say anymore what you do while you’re here, but under my roof he’s not allowed in your room!”

“I-I’ll leave, sir!” They were approaching the stairs and Adachi knew in this position he wouldn’t fair well, grateful when Dojima actually released him. “I didn’t mean any harm.”

Dojima opened and closed his mouth without saying anything. Adachi should not have been in his niece’s bedroom, but he did want to believe they’d only fallen asleep together. It was just hard for him to imagine the young woman he saw as a second daughter being in an intimate relationship that started because he’d thought nothing of introducing the two of them. If Adachi ended up breaking her heart Dojima would be devastated.

To see him curled up with her, hands cupping her breasts, made it hit home just how far their relationship must have gone. There was no way it hadn’t began when she’d spent a year with him.

When Adachi was gone, Dojima confronted Narukami in the hall. Nanako kept her door open only a crack to spy on them. Her father would take Narukami somewhere else if he knew she was awake.

“I want the truth. When did this all start.”

Adachi had prepped Narukami for this. She knew exactly what to say, but lying to her uncle was the hard part. “When you and Nanako-chan were at the hospital. My friends care about you both so much it took its toll on them too. If they saw me cry, I knew they’d worry even more. Tohru came over and I could tell him how scared I really was about Nanako’s condition.” She hesitated. “I… I kissed him. He thought it was just because of the situation, but said he’d wait for me to be certain of my feelings.”

It was the perfect response to dupe Dojima; he was still blissfully ignorant of Adachi’d true nature and what he’d done to his niece at the police station. Any guy would be a fool to turn down such a pretty girl’s advances, and she was nearly an adult at the time.

“Just don’t let it happen again.”

Narukami promised.

 

The awkwardness everyone felt couldn’t be helped. Dojima’s night shifts were over, so any nighttime fun was ceased, but Narukami still managed to spend enough time one-on-one with Nanako and be able to give Adachi the intimacy he wanted at his house.

Adachi and Nanako spoke very little when they were together. Narukami still thought jealousy was to blame, asking the two on a walk with her one late afternoon in the hopes of finding a way to overcome it since Nanako wouldn’t talk about it.

The people of Inaba were used to the fog, but it still contributed to getting them indoors sooner the moment it started getting dark. Sometimes the thickness was so bad you couldn’t see a hand in front of you face, but Narukami and Adachi had zero issues with that. Narukami found she didn’t even needs her glasses anymore.

Nanako just kept a firm hold on her hand. She couldn’t see much, but would go anywhere her Big Sis wanted.

The walk was quiet with a heavy atmosphere, Adachi only speaking up when he wanted to enter a shop to use the restroom. The two girls waited for him outside in the quiet, barren Shopping District where even more shops had closed, when two sloppy looking men approached them.

“Hey, sweetie,” One of the men said when they got close, not realizing until then how gorgeous Narukami was. “What you doing out here? Looking for some company?”

“I’m with my sister and my boyfriend will be right back,” Narukami answered, stepping in front of Nanako. She already had a bad feeling.

“Then he can take your sister home. Come hang out with us.” He suddenly grabbed her arm, making Nanako gasp.

“Let go!” She tried to pull away.

“Don’t touch her!” Nanako hit the man as hard as she could in the stomach, only getting a laugh in response. She was too small to hurt anyone.

“What’s going on?!” Adachi returned not a moment too soon, but the thugs weren’t intimidated a bit. Adachi didn’t look even remotely like a threat. “Get away from her or I’ll-”

“You’ll what?” The second man shoved Adachi hard, making him stagger back and nearly fall down. “Well? I’m still waiting!” His friend laughed as he approached Adachi.

He went to put his hands on Adachi again, surprised when Adachi fought back and struck him under the eye with decent force. It only stunned him for a moment, Nanako and Narukami screaming when he slammed Adachi into a wall and delivered a punch of his own, making him see stars.

“P-police!” Adachi reached for his badge out of desperation and pulled it out. “I’m armed!”

Thankfully his bluff of having his weapon on him was enough. The men gave up and ran away immediately, Narukami going to Adachi’s side. He would be alright, but the man had really hit him with all of his might. They took him back to the Dojima residence since it was closest, Dojima writing down a description of what the two men looked like while Narukami wrapped some ice in a cloth, delicately placing it against Adachi’s already bruising face to hold.

“I’ll phone this in,” Dojima said.

Adachi shook his head. “It’s not worth wasting time over; I’m the only one who got hurt. As long as they’re OK we can let this go. I didn‘t recognize them so I think they were just passing through.” He sounded so noble, but the truth was he didn’t want to deal with making it a case and adding more work for himself when his vacation time was over.

Dojima couldn’t help smiling slightly. “Then I’ll order some takeout for us. Anything you want.”

“R-really?”

“Thank you for protecting them.”

“You were so brave,” Narukami added.

Nanako couldn’t help agreeing, getting up from beside Narukami so she could stand in front of Adachi. “…I guess it’s alright if you date her.”

Adachi couldn’t help chuckling, but the pain cut it short. “Glad to have your approval,” he said as he winced, pressing the ice pack tighter against his jaw.

“But if you hurt her I’ll hate you forever!” She threatened.

“I won’t. Still friends?”

“Yeah.” Nanako hugged Adachi, Dojima smiling and Narukami tearing up. It looked like their family was going to be fine after all.


End file.
